Well treatment



April 4, 1961 R. H. wlDMYl-:R

WELL TREATMENT Filed Jan. 20, 1958 y fmt/WFP, 27

United StatesPatent O WELL ruEA'rn/IENT Richard H. Widniyer, Houston, Tex., assignor to 'VTexaco Inc., a corporation of Delaware Filed Jan. zo, 195s, ser. No. 710,058

' 'fs claims. (c1. 16s-s1) producing formation one difculty sometimes encountered, particularly whenV the petroleum producing formation is an unconsolidated formation, is that the, producftivity of the well becomes reduced after a period of time due to the sanding upor.pluggingfof` therwell.

sandingup it has been `proposedto gravel pack a well. In' a gravel ,packingoperation a .lter bed of porous granular material is deposited withinthe` well bore adjacent the petroleum` producing formation;V This porous'gravel bedfserves to support the adjacent petroleum producing formation and tends to prevent the well bore from sanding upldue to` the transportof finely divided solid material from the producing formation intothewellbore. I f .jV Recently it `has been proposed, see U.S. yPatent No. 2,814,347, issuedNovembfer 26,1957, Vthe disclosure of which is herein incorporated and` made part of this disclosure, to carry out a gravel packing operation and formation fracturing operation substantially Vsimultaneously. The' operationsdisclosed therein, however,

are complicated andifrequireV the use `of av rather large` amount ofequipment and production tubing o1"` conduit.

It is, therefore, an Vobject of this inventionto'provide an improved apparatus `for well treatment.

To` avoid this reduction in well productivity dueA to the well is obtained by disposing a well screen or liner within a well bore adjacent a petroleum producing formation and then carrying out asubsequent gravel packing operation in such a manner that the material (carrier liquid and granular solids) employed inthe gravel packing operation isintroduced into the well bore into contact with the petroleum producing formation undergoing treatment via the production tubing. The production tubing after completion of the well treatment or gravel packing operation is then employed to carry Y the produced petroleumfrom the resulting treated' formation.

Referring now to the accompanying drawings, and particularly Fig. 1 thereof which schematically illustrates an apparatus suitable for use in an operation in accordance with this invention involving gravel packing in combination with formation fracturing, there is ilr lustrated a well bore 11 provided with casing 12. As illustrated, the casing 12 terminates within well bore 11 above the petroleum producing formation 14. Provided within casing 12 is production tubing 15. Releasably attached to the bottom end of tubing 15 is well screen or liner 16 which is disposed within well bore 11 adjacent the petroleum producing' formation 14. screen 15, is shown releasably attached or threadedly engaged to the `lower end of tubing 15, the upper inside portion of well screen 16 being provided with a shoulder or'stop 17 against which the bottom end of tubing abuts. A packer 18 is positioned in the annular space between lcasing 12 and production tubing 15 above a normally closed discharge outlet or valve 19 provided in the thickened lower portion or mandrel of tubing 16. e

- Wire line 20 adapted to be lowered by suitable means (not shown) within tubing 15 has attached to the lower end thereof sleeve 21 the lower end of which is closed and which is adapted to snugly fit within the lower inside portion of production tubing 15. The sleeve 21 is provided with an opening 22 in the upper portion thereof and'anoritice 24 positioned and adapted to cooperate or to match the discharge outlet 19 in the lower portion of tubing 15. While only one orice 24 with one discharge outlet 19 is shown in the drawing, it is pointed out that a multiplicity thereof may be used to provide It is another object of this invention to providefan irnproved apparatus for effecting gravel packing andformation `fracturing substantially simultaneously;

Another object of this invention is to vprovide anv an'improved apparatus suitable 'for use yin pressure; gravel KVcompa'nyin'g disclosure 'made withl referrce'to the 'accompanying drawings whichsche'matically illustrate'ern-- bodimentsof the practice'of'this 'invention-'particularly useful for carrying outa combination well grav'elpacking fand'fracturing operation andA wherein Fig. 1 schematr ically illustrates the operation andassembly of apparatus'` employed in an operation in accordance with 'an embodiment of this invention and wherein" Fig. 2 schematically illustrates the operation and assembly of apparatus emk ployed in an operation in accordance with anothereni-V bodiment of this invention. Figs. 3a and 3b are expanded views ofthe valvev opening operation. i In'atl least one embodiment of the practice of this invention at D least one of the ,foregoing objects is acctgniplislied.V A VIn accordanceA with this invention it-has now 'been for a higher injection rate. The sleeve 21 fits snugly within the inside of the lower portion of tubing 15 to provide a substantially fluid tight seal therebetween. Further, as clearly indicated inthe drawing, well screen 16 "is provided with slits or perforations 25 so that the mixture of gravel anducarrierv liquid llows through tubing' .'15 throughrthe.' opening 22 `in the upper portion of sleeve 21 and outwardly therethrough through orice 24 and dischargeoutlet' 19. The vsleeve,l\yvhe'n positioned as illustrated in Fig. 3b of the accompanying drawing, serves tomaintain the valve 19 in an open position, as illusn rtrated.' A sufficient amount of liquid, together with granular material, `is introduced to fill the annular space between well screen'16 and welllbore 11. The carrier Voutside well screen 16 within Vthe annular space thereabout since ,the granular material` is too largeV to 'pass A l through the `slots or perforations 25 of lwell screen 16..` discovered that an improved well completion operation Further, since packer 18 is closed-back ow of the mix" l Well ture of carrier liquid and granular material upwardly into casing 12 is prevented so that any pressure exerted upon the liquid within the well bore 11 surrounding well screen 16 is in turn exerted substantially exclusively against the petroleum producing formation 14.

Pressure, by suitable means such as a pump (not shown), such as fluid pressure exerted by a liquid filling tubing is then exerted upon the liquid filling in the interior of well screen 16 and the surrounding annular space within well bore 11. The pressure exerted is suiiicient to force at least a portion of the mixture of carrier liquid and granular material within the annular space surrounding well screen 16 into the petroleum producing formation 14.

Desirably the pressure exerted upon the mixture within the annular space surrounding well screen 16 is sufficient to fracture the petroleum producing formation. When a fracture 27 occurs, as illustrated in the drawing, at least a portion of the mixture of carrier liquid and granular material is forced into the formation, the granular material occupying fracture 27. Sufficient pressure may be exerted upon the mixture within the annular space surrounding well screen 16 to enlarge the resulting fracture 27 to any desired extent. Since the interior of well screen 16 and the annular space within the well bore surrounding well screen 16 are in direct ffuid communication substantially the same fiuid pressure would exist withinthe interior of well screen 16 and the surrounding annular space. Further, as previously mentioned, with packer 13 positioned and closed as illustrated the fiuid pressure exerted upon the liquid within the well bore surrounding well screen 16 is readily maintained and exerted substantially exclusively against the petroleum producing formation 14 undergoing treatment.

When the petroleum producing formation 14 has been gravel packed, and desirably fractured, such that there remains a fracture 27 within the petroleum producing formation with gravel deposited therein, as well as a residue or bed or pack of granular material within the annular space defined between well screen 16 Vand the adjacent petroleum producing formation, as illustrated in the drawing, the pressure exerted upon the mixture within the annular space surrounding well screen 16 is released. Wire line 2t) then lifts sleeve 21 from within the inside of tubing 15 and returns sleeve 21 to the surface and is withdrawn. As sleeve A21 is moved away from within the bottom of tubing 15 the normally closed discharge outlet 19 in tubing 15 is closed (see Fig. 3a). Following the aforesaid operations the well is swabbed and petroleum production resumed from the resulting treated petroleum producing formation 14 via fracture 27, the mass of gravel in the well bore therein surrounding well screen 16, then through well screen 16, an production tubing 15.

Referring now to Fig. 2 of the drawing which discloses an apparatus similar to that disclosed in Fig. 1 the same reference numerals have been employed to identify similar elements of the drawing. As illustrated in Fig. 2

the sleeve 21 adapted to fit snugly within the lower end or mandrel portion of production tubing 15 is attached,

such as threadedly engaged, to the lower end of a string of tubing 30. Tubing string 30, like the interior of production tubing 15 of Fig. 1, is in direct fluid communication with the interior of lsleeve 21 and is employed to position sleeve 21 within the lower end or mandrel portion of tubing 15 so as to open normally closed' discharge outlet 19 therein. Further the string of tubing 30 is employed to carry the gravel packing admixture of carrier liquid and granular material into sleeve 21 and outwardly through orifice 24 and discharge outlet 19 into the well bore 11 surrounding well screen 25. As in Fig. 1, if desired, a plurality of discharge outlets 19 and orices 24 might be employed in combination; The string of tubing 30 is also adapted to be moved upwardly within production tubing 15 and to move sleeve 21 away from the lower end of production tubing 15 and discharge outlet 19 therein so that discharge outlet 19 is closed (see Fig. 3a). When tubing 30 together with sleeve 21 attached thereto is removed from the lower end of production tubing 15 production of petroleum from petroleum producing formation 14 is resumed in the manner already described hereinabove with respect to the employment of the apparatus illustrated in Fig. l.

Figs. 3a and 3b show the operation by which the valve 19 is opened. Tubing 15 is modified to define a slot 15' in which is mounted detent 21 either fixedly and preferably pivoted. As the sleeve 21 descends in the tubing 15, it moves the detent 21 through the outlet 19 to force the valve 19 outwardly as shown in Fig. 3b so that the orifice 24 in sleeve 21'is aligned with the discharge outlet 19.

Although the drawing shows well bore 11 penetrating the petroleum producing formation 14 to be an open hole therein, it is pointed out that the practice of this invention is applicable to the treatment of a cased and perforated petroleum producing formation. When the petroleum producing formation is provided with a perforated casing the mixture of granular material and carrier liquid is forced into the petroleum producing formation via the perforations in the casing and a tiuid pressure exerted through these perforations sufficient to fracture the formation.

Various fluids may be utilized as the carrier liquid employed in the gravel packing operations in accordance with the practice of this invention. These fluids include the normally liquid hydrocarbons, crude petroleum, lease crude, petroleum fractions, crude oil or kerosene, lease crude or petroleum fractions such as diesel oil or kerosene thickened with a suitable thickening or gelling agent such as sodium palmitate (napalm) and the like. Aqueous liquids, such as water, thickened or unthickened with additives which increase the viscosity thereof and reduce fiuid loss, as well as brines, such as formation brines, may be suitably employed as a carrier liquid in the gravel packing operation described herein.

As` will be `apparent to those skilled in the art many modifications, changes and alterations are possible in the practice of this invention without departing from the spirit or scope thereof.

I claim:

1. An assembly for use in the completion of a well bore having a casing and comprising tubing disposed within said casing and being provided with a valve adjacent the lower end thereof for normally closing an outlet therein, means adapted to engage said valve for opening of the same movably mounted on and projecting into said tubing, a well screen attached to the lower end of said tubing, a fiuid tight packer sealing off the annular space betweensaid casing and said tubing in contact with said tubing above the normally closed outlet, a sleeve adapted to be raised and lowered within said tubing and positioned therewithin adjacent said well screen to provide a substantially liquid tight seal therewith and in one direction of longitudinal movement to actuate the first mentioned means by movement thereof to engage and open'said valve, said sleeve having an orifice therein for alignment with said outlet and an opening -for providing fiuid fiow therethrough from said tubing into said sleeve and out through said orifice and said outlet aligned therewith.

2. In an assembly as defined in claim 1, said sleeve having a wire joined thereto Vfor raising and lowering thereof.

3. In an assembly as defined in' claim l, a string of tubing joined to said sleeve yand providing means for raising and lowering thereof and for providing a fluid ffow path therethrough.

References Cited in the Vfile of this patent Y UNITED STATES PATENTS 2,224,538 Eckel-et al. Dec. 10, 1940 2,814,347 MaCKnght ...7 NOV. 26, 1957 2,906,338 Shook Sept. 29, 1959 

